The objective of this study is to investigate the natural history of coronary heart disease using data collected on post myocardial infarction patients from the Beta-Blocker Heart Attack Trial (BHAT). The BHAT is scheduled to end December 31, 1983. The analyses proposed here are those that the BHAT study investigators will not have time to conduct and finish by the end of the contract. Over a two year period 3837 patients were randomized into the BHAT 5 to 21 days after the onset of their acute symptoms and were followed for 12 to 40 months (average = 25 months). Men and women, age 30 to 69 years of age were eleigible for the trial. Using lifetable methods and linear and logistic regressions, most of the proposed analyses will examine the relationship between specified baseline variables and subsequent events in the BHAT placebo patients. The baseline variables describe the sociodemographic, medical history, medication use and physical examination characteristics of the patients and include 12 lead resting and 24 hour ambulatory ECGS. The study endpoints will be all-cause mortality, cause-specific mortality, recurrent non-fatal myocardial and incident congestive heart failure studied separately. One other analysis will examine the baseline association between the occurrence of ventricular premature beats as detected on the 24-hour ambulatory ECG and activities occurring during the day in the entire BHAT population.